DESCRIPTION (Obtained from the applicant's abstract): The ligand for the c-kit receptor functions as a potent growth factor and differentiation inducer for very early hematopoietic stem cells. The kit ligand protein is currently being evaluated by several labs for therapeutic utility in combination with other hematopoietic growth factors for the treatment of anemia and leukopenia. Weare proposing to develop a system to identify small molecular weight compounds which function to increase the expression of the patients's own Kit Ligand (KL) gene. Such compounds could potentially be used as pharmaceutical to increase the effectiveness of, or reduce the requireddosage of, therapeutically administered hematopoietic growth factors like erythropoietin or G-CSF. Our technical approach is to: 1.Fuse the KL transcriptional regulatory elements to the firefly luciferase gene. 2. Use this reporter construct to create a stably transfected KL-luciferase reporter cell line, and 3. Use this cell line (and appropriate controls) to analyze natural products extracts and chemical files seeking compounds which specifically up-regulate KL transcription. The cell line construction will be completed, tested and screening initiated during Phase II. The project will be commercialized by establishing a collaboration with a major pharmaceutical company to continue the process of drug development.